<template>
  <div>
    <ul>
      <li :style="{opacity}">欢迎学习Vue</li>
      <li>news001<input type="text"></li>
      <li>news002<input type="text"></li>
      <li>news003<input type="text"></li>
    </ul>
  </div>
</template>

<script>
export default {
  name: 'News',
  data() {
    return {
      opacity: 1
    }
  },
  // mounted() {
  //   this.timer = setInterval(() => {
  //     this.opacity -= 0.01;
  //     if (this.opacity <= 0) {
  //       this.opacity = 1
  //     }
  //   }, 16)
  // },
  // beforeDestroy() {
  //   clearInterval(this.timer)
  //   console.log('News即将被销毁了');
  // }

  activated() {
    console.log('News组件激活了');
    this.opacity = 1;
    this.$nextTick(() => {
      this.timer = setInterval(() => {
        this.opacity -= 0.01;
        if (this.opacity <= 0) {
          this.opacity = 1
        }
      }, 16)
    })
  },
  deactivated() {
    clearInterval(this.timer)
    console.log('News组件失活了');
  }
}
</script>

<style >
</style>